Tire-vulcanizing press

ABSTRACT

A tire-vulcanizing press which has particular application to tires of smaller size, e.g. those used for private cars including a heating bag arranged folded double between an inner and an outer cylinder on the lower part of a press, the inner cylinder acting as a bag-guiding cylinder and having means for positioning the cylinder at different levels and the outer cylinder acting to eject a tire from the lower half of a mould, and means on the closing of the press to adjust the height of the inner cylinder and thus the amount of the bag within a tire.

United States lnventors Appl. No.

Filed Patented Assignee Priority aet Walter Balle Dornigheim;

Gunter Pommer, Frankfurt am Main, Germany May 16, 1969 Apr. 13, 1971Leonhard Herbert Maschinenfabrik May 17, 1968 Germany TIRE-VULCANISINGPRESS 5 Claims, 5 Drawing Figs.

US. Cl 18/17, 18/2 Int. Cl 82% 5/02 Field of Search 18/17 (K,

[56] References Cited UNITED STATES PATENTS 2,730,763 1/1956 Brundage2,736,059 2/1956 Frank 2,858,566 11/1958 Brundage 8/ 1968 Balle et al.

Primary ExaminerJ. Howard F lint, J r. AttorneyWatson, Cole, Gn'ndle &Watson 18/17 18/17 18/17 l8/l7X ABSTRACT: A tire-vulcanizing press whichhas particular application to tires of smaller size, e.g. those used forprivate cars including a heating bag arranged folded double between aninner and an outer cylinder on the lower part of a press, the innercylinder acting as a bag-guiding cylinder and having means forpositioning the cylinder at different levels and the outer cylinderacting to eject a tire from the lower half of a mould, and means on theclosing of the press to adjust the height of the inner cylinder and thusthe amount of the bag within a tire.

Pmnied ml 13, 1971 I 3,574,893

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Patented A ril 13, 1911 i. 3,574,893

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' Inventor V1412 Z A BaZZe 6 712 6 P0 mm TlRE-VULCANISING PRESSBACKGROUND OF THE INVENTION The invention relates to a tire-vulcanizingpress for the vulcanization of preformed tire carcases, which hasparticular, though not exclusive, application to tires of small sizeswhich are to be retreaded, e.g. tires for private cars, and whichincludes a heating bag which may be inserted whilst folded double intoan annular space between two cylinders arranged one within the other andrelatively movable axially, the outer of these two cylinders carrying anannular rim seat and the inner cylinder acting as a guide for the bag.

Tires of different dimensions can be vulcanized on a tirevulcanizingpress of a given size, it being necessary to install the appropriatemould in the press for each tire size. In the case of large tires, asemployed for commercial vehicles, a relatively small number of differentsizes is in use, whereas a multiplicity of different sizes is'in use inthe case of smaller tires, as used on private cars. For this reason, itmay be acceptable to change the heating bag during conversion, which israther infrequent, for another tire size, during production orretreading of large tires. It is preferable however to avoid theexchange of this heating bag in the case of the vulcanization of smallertires, and in particular in the case of retreading them, different tiresizes occurring very frequently, because a relatively long workingperiod would be lost by adapting the presses, and very many bags ofdifferent size would have to be stocked.

The expansibility of the heating bag easily renders it possible tovulcanize tires of different size with one and the same bag, if care istaken to ensure that only such part of the bag as correspondsapproximately to the tire size, is inserted into the cavity of the tire.

Different devices are known to effect such an adjustment of the heatingbag. In the case of presses possessing a driving mechanism for theinsertion of the bag, it is thus known to fit exchangeable stops to thedriving mechanism, which establish different vertical levels of ringsclamping the bag. In the case of vulcanizing tires of larger crosssection, into which a considerable part of the bag is inserted, thestops employed are shorter, whereas longer stops are employed in thecase of vulcanizing tires of smaller cross section into which a smallerpart of the bag is inserted. It is also known to employ and adjustingspindle instead of exchangeable stops. A scale must be incorporated inthis case, which indicates the correlation between the position of thenut on the spindle and the tire size.

In the case of an electrically motorized driving device for the bag, ithas already been suggested, moreover, that an electric motor supplyingthe driving power for the insertion of the bag, be switched offaccordingly by means of a camoperated switch.

the present invention is based on the problem of devising a structurallyuncomplicated heating bag setting device for a press of the kindinitially referred to, which renders it possible to place the heatingbag in the correct working position without employing setting scales ormeasuring operations, under exclusion of exchangeable parts.

SUMMARY According to the present invention, there is provided atirevulcanising press for vulcanizing preformed tire carcasses,including an upper part and a lower part, a mould having an upper halfon the upper part of the press'and a lower half on the lower part of thepress, and an assembly on the lower part of the press having an outercylinder, a seat ring for a tire rim on the outer cylinder, a drivingsystem for the outer cylinder, the outer cylinder being movable axiallybythe driving system to eject a tire from the lower half of the mould,an inner cylinder within the outer cylinder, a locking device forholding the inner cylinder at a predetermined level, a heating bag whichmay be arranged when folded double in the annular space between theinner and outer cylinders, clamping rings connected to the innercylinder between which the edges of the bag may be clamped, andresilient means for urging the inner cylinder towards and against a partconnected to the upper part of the press during the closing of thepress.

The invention exploits the fact that the so-called aperture i.e. the gapbetween the rims of a tire, has an approximately constant relationshipto its internal periphery measured in a radial sectioning plane. Theaxial rim gap thus provides an approximate measure for the internalperiphery of the tire, so that the setting of the heating bag may bemade a function of the rim gap. A setting corresponding to the rim gapis now available in a press according to the invention. The greater therim gap, that is to say the greater the bag length to be inserted intothe tire, the shorter the distance through which the bagguiding cylinderwith the bag attached thereto is thrust back, since the upper half ofthe mould, a component of which makes a rearward displacement, does notcome as close to the lower part of the press for a tire having a greaterrim gap, as for a tire having a smaller rim gap. The upper half of themould thus thrusts back the clamping points of the bag, i.e. its lowerclamps, precisely as far as to ensure that only such part of the bag asis required for fully lining the tire cavity with the bag, stillprojects into the tire cavity. Ifthis position is reached during thefirst closing of the press, the corresponding position of thebag-guiding cylinder is maintained by the locking device and no longerchanges during subsequent vulcanization of tiresof the same size.Devices according to the invention are structurally extremely simple andperfectly reliable, and operate in an almost wholly automatic manner.All that is needed is to lock the immobilizing device, which operationcould easily be made automatic moreover.

In a preferred embodiment of the invention, the part of the upper halfof the mould which thrusts the bag-guiding cylinder back into thecorrect working position, consists of an upper tire rim seat ring. Tothis end, the upper tire rim seat ring has formed on it a narrowinferior annular area which bears against a corresponding annular areaof the bag-guiding cylinder in the closed position of the press. Thisannular area on the bag-guiding cylinder may be formed on the base ofthe bag-guiding cylinder. This base may simultaneously form an elementof the bag-clamping system, namely the upper bagclamping ring. Theapplication of the upper rim seat ring as the element exerting aretracting thrust is advantageous because the upper rim seat ring is themost widely projecting element which can easily be brought into contactwith the bagguiding cylinder. In principle, it is possible however toemploy a separate abutment for this purpose.

On the base of the bag-guiding cylinder there may be situated a centraland downwardly extending rod which cooperates with an immobilizing orlocking device firmly connected to the lower part of the press. Thislocking device may be a clamping sleeve enfianking the rod, which can beopened and released by means of one or more clamping screws accessiblefrom the outside of the press. As shown by practical tests, a clampingsystem of this nature may easily be wrought so robustly that thebag-guiding cylinder is not forced back even when the full internalpressure of the heating bag acts on the press. The cooperation between arod and a clamping sleeve also allows for infinitely variable adjustmentof the vertical position of the bag-guiding cylinder.

Below its clamped area, the rod may be encircled by a coil compressionspring, the lower extremity of which bears on the lower part of thepress and the upper extremity of which bears on a shoulder formed on therod, constantly exerting a force on the rod impelling the same upwards.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention willnow be described with reference to the accompanying drawings in which:

FIG. 1 shows a vertical radial section through a press in the statefollowing the placing in position of a tire to be vulcanized forretreading purposes, the upper part of the press already having beenlowered a little;

FIG. 2 shows a similar view to that of FIG. 1 with the press in acondition in which a pressurized fluid cylinder exerts a thrust on anejector cylinder, and an initial inflation pressure has already beenestablished in a heating bag;

FIG. 3 shows a view similar to that of FIG. 1 with the press closedcompletely and the heating bag under pressure;

FIG. 4 shows a radial section through the press in the area of the mouldon an enlarged scale compared with that of the preceding FIGS.; and

FIG. 5 shows a section corresponding to that shown in FIG. 4, during thevulcanization of a tire of greater size.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings it maybe seen from FIG. 1 that the press has a lower part 1 which carries alower half 2 of a mould, and an upper part 3 displaceable relative tothe lower part and on which there is the upper half 4 of the mould. Thedisplacement of the upper part 3 of the press with respect to thestationary lower part 1 of the press is achieved by means of a powerfuldriving mechanism which is not illustrated and which is arranged toprovide a substantial closing pressure.

The lower part 1 of the press includes a platform or table 5, a part 6of the lower half 2 of the mould carried on a heating plate 7 and beingarranged on this table with the interposition of an insulating plate 8.There is a wide opening 9 in the table, from which a projection 10extends downwards. At its lower end the projection 10 carries a robustbase 11.

The base 11 has secured to it a driving system provided by two pressurefluid cylinders 12 and 12b in which are slidable double-acting pistons,having piston rods 13a, 13b fastened to a base 14 of an ejector cylinder15. On its upper edge, the ejector cylinder 15 carries a lower rim seatring 16.

A bag-guiding cylinder 17 is coaxially arranged relative to the ejectorcylinder 15. A heating bag 18 is clamped fast on the lower extremity ofthis bag-guiding cylinder. This heating bag is folded double about afolding point 19. The heating bag I has two edges having respectivebeads 20 and 21 which are clamped fast onto the lower extremity of thebag-guiding cylinder 17. The upper bead" 20 is clamped between a loweredge 22 of the bag-guiding cylinder 17 and a spacing ring 23, and thelower bead is clamped between the spacing ring 23 and a lower clampingring or plate 24. The lower edge 22, the spacing ring or plate 23 andthe lower plate 24 together form an assembly which may be fastened on toa baseplate or lower clamping ring 25, in such a way that the parts ofthe assembly are pressed against each other tightly so that any ingressof fluid under pressure form the clamping points of the beads 20, 21 isimpossible. An intermediate space 26 for the reception of the bag 18 issituated between the ejector cylinder 15 and the bag-guiding cylinder17. i

A central and downwardly projecting rod 27 of circular cross section issituated on the bag-guiding cylinder 17. This rod 27 passes through aclamping sleeve 28 which forms a locking device and which is firmlyconnected to the base 11 of the projection 10 from the press table 5.The clamping sleeve 28 has a cut in radial direction at one point, and aclamping screw 29 which extends at right angles to the cut or slit isprovided by means of which the clamping sleeve can be compressed so asto clamp the rod 27 fast.

To the base 11 there is also secured a sleeve 30 having a base 31 andsurrounding the rod 27. In an annular space between the sleeve 30 andthe rod 27 there is situated a compression coil spring 32 which bearsagainst the base 31 of the sleeve 30 at the bottom and against ashoulder 33 of the rod 27 at the top. The initial loading of the springis such that it tends to press the rod 27 upwards at all times.

The rod has a central bore 34 forming a pressure fluid feed pipe andopening near the top into a radial bore 35 in the spacing plate 23. Theradial bore leads into the cavity of the bag-18.

Another element on the lower part I of the press is a thrust rod 36connected to the base 14 of the ejector cylinder 15,

and having an upper end face 37 which acts as a stop in manner yet to bedescribed.

The upper part 3 of the press has a fastening plate 38, with aninsulating plate 41 and a heating plate 40, on which there is secured apart 39 of the upper half 4 of the mould. On the plate 38 there isarranged an upwardly extending projection 42 which is closed off at itsupper end by a plate 43. On the plate 43 there is arranged a pressurefluid cylinder 44 whose effective cross section is greater than thetotal effective cross section of the two lower pressure fluid cylinders12a and 12b. On the piston rod 45 of the piston sliding in the cylinder44 there is fastened the base 46 of a cylinder 47 which carries an upperrim seat ring 48 on its lower extremity. This upper rim seat ring 48 hasa narrow lower end face 49 as well as a conical surface 50. The functionof these surfaces is yet to be described. A thrust or abutment rod 51projects downwards from the cover 46 of the cylinder 47. This thrust rodis aligned with the lower thrust rod 36. Its lower end face 52 is anabutment surface and can cooperate with the abutment surface 37 of thelower rod 36.

The bag-guiding cylinder 17, with the bag fastened to it, and theassociated parts, are shown in greater detail in FIGS. 4 and 5. It maybe seen from FIG. 4 that the bag-guiding cylinder 17 extends downwardlyand has a bag-clamping ring 53 which has a narrow annular surface 54.The ring 53 is screwed to the spacing ring 23 by means of studs 55 andnuts 56. Another screwed connection, not illustrated, is made betweenthe lower clamping ring 25 and the spacing ring 23. In the ring 53 andthe spacing ring 23 there are grooves which together form a crosssection in which the upper bead 20 of the bag 18 is clamped fast.Grooves are also formed in the ring 25 and the spacing ring 23, togetherforming a cavity for clamping the lower bead 21 of the bag.

The rod 27 has a shoulder 58 on which the plate 25 rests. The plate 25is welded to the rod. The diametrically neckeddown upper part of the rod27 has a neck portion of reduced diameter which passes through thespacing ring 23. A nut 57 presses the assembly consisting of the upperring 53, the spacing ring 23 and the lower ring 24 against the baseplate25 through the spacing ring 23 and the ring 24.

The operation of the press will now be described.

It is assumed that a preceding vulcanizing cycle has been completed andthat a vulcanized tire has already been stripped from the mould. In thiscase, the elements of the lower part of the press will be situated inthe position shown in FIG. 1, in which the bag 18 has disappeared almostcompletely into the annular space 26 between the ejector cylinder 15 andthe bagguiding cylinder 17. A tire 59 to be retreaded, which is alreadycoated with crude rubber, has been placed on the lower rim seat ring 16.Furthermore in the arrangement shown in FIG. 1 the downward displacementof the upper part 3 of the press has already started. Together with thedownward displacement of the upper part 3 of the press, the upper rimseat ring 48 is moved downwards, relative to the upper part 3 of thepress, under the action of the pressure fluid cylinder 44. The ring 48passes the bag-guiding cylinder and finally bears on the upper rim ofthe tire. The upper part 3 of the press now continues its downwardmovement (see FIG. 2) until the rods 51 and 36 come into contact. Theupper rod 51 thereupon causes the ejector cylinder to be presseddownwards. This is possible since the upper pressure fluid cylinder 44develops a greater force than the two lower pressure fluid cylinders 12aand ll2b together. During this downward displacement of the ejectorcylinder 15, the ejector cylinder 15 slides along the bag 18, and thebag is guided into the tire cavity by the conical surface 50 on theupper rim seat ring 48. When the heating bag 18 has been substantiallyinserted into the tire cavity, a little pressure (initial inflationpressure) is fed to the bag through the pressure fluid feed pipe 34, sothat the bag is brought against the inner side of the tire. The heatingbag is fully inserted into the tire when the upper half of the mouldbears on the lower half of the mould.

At the end of the closing operation, the lower annular surface 49 of theupper rim annulus 48 is placed on the annular surface 54 on the ring 53(see FIG. 4). At this time, the pressure fluid cylinders 12 and 12b arealso actuated in such manner as to move the ejector cylinder 15downwards until the lower rim seat ring 16 is brought into contact withthe part 6 of the lower half of the mould. The rods 51 and 36 are againdrawn apart slightly during this action (see FIGS. 3 to 5).

Internal pressure is now built up in the heating bag and thevulcanization of the tire is begun. Upon opening the press aftercompletion of the vulcanizing operation, the upper part 3 of the mouldis raised first, thereby being removed from the upper side of the tire59. The upper rim seat ring 48 may be controlled at the same time insuch manner as to hold down the tire so that the tire cannot beentrained by the upper half of the mould. The ejector cylinder 15 isthen raised and removes the vulcanized tire from the lower half 2 of themould. The tire is then lifted off the lower rim seat ring 16 manually,and another tire to be vulcanized is placed on the ring 16. The clampingsleeve 28 and thus the position of the bag relative to the lower part ofthe press remain unchanged, for as long as the same tire size is to beprocessed. With a tire of a size which corresponds to that shown in FIG.4 it is unnecessary as may be seen from FIGS. 3 and 4 for the entireheating bag to be inserted into the tire cavity. From FIG. 4 it may beseen that a surplus portion 60 of the bag remained in contact with theinner side of the lower rim seat ring 16, owing to the fact that thebag-guiding cylinder with its clamping device for the bag had beenadjusted to the corresponding depth.

If however a tire of another size were to be handled necessitating theinsertion of the entire bag into the tire cavity (see FIG. 5), the upperand lower rim seat rings as well as the two halves of the mould giving aheight h, (FIG. 4), would be dismantled initially. A new mould (heighth,, FIG. 5) and the corresponding rim seat rings, would then beinserted. The same rim seat rings as inthe previous case may be employedif the tire in question has the same diameter as that of the tirepreviously processed. After this assembly change the press is closedpartially, and the locking device 28 on the rod 57 is released byloosening the screw 29. The spring 32 then thrusts the rod 27 and theclamping rings, upwards. The spring is so dimensioned that the clampingrings are thrust into a slightly higher position than is necessary forthe widest tire that can still be processed in the press.

The press is then closed, the lower annular surface 49 of the upper rimseat ring 48 being placed on the annular surface 54 on the base ring 53of the bag-guiding cylinder 17, and rearwardly displacing thebag-guiding cylinder together with the rod 27 against the force of thespring 32, the spring 32 being compressed thereby. When the pressis'closed completely, the clamping rings are situated at precisely theheight for clamping points of the bag to be correctly positioned withrespect to the tire. This is attributable to the fast that the rim gap m(FIG. 5) of a tire has an approximately constant relationship with thecross-sectional periphery U of the tire. As may be seen by comparingFIGS. 4 and 5, the clamping points of the bag are now situated at ahigher level relative to the tire than before, so that a greater part ofthe bag is inserted into the tire cavity, being almost the whole of thebag in the present case. After closing the press, the clamping sleeve 28is clamped tight again, thereby locking the vertical level of the bag.Freeing then becomes necessary only for adaptation to another tire size.

It is apparent from FIG. 3 in particular, that the pressure fluid bore35 opens into the bag at the lowest point. This has the advantage ofsatisfactory and speedy draining, since when the fluid used is water anysteam formed during draining above the surface of the water exertspressure on the surface of the water and forces the water out throughthe outflow bore.

l. A tire-vulcanlzlng press for vulcanizing preformed tire carcasses,including an upper part and a lower part, a mould having an upper halfon the upper part of the press and a lower half on the lower part of thepress, and an assembly on the lower part of the press having an outercylinder, a seat ring for a tire rim on the outer cylinder, a drivingsystem for the outer cylinder, the outer cylinder being movable axiallyby the driving system to eject a tire from the lower half of the mould,an inner cylinder within the outer cylinder, a locking device forholding the inner cylinder at a predetermined level, a heating bag whichmay be arranged when folded double in the annular space between theinner and outer cylinders, clamping rings connected to the innercylinder between which the edges of the bag may be clamped, andresilient means for urging the inner cylinder towards and against a partconnected to the upper part of the press during the closing of thepress.

2. A tire-vulcanizing press as claimed in claim 1, including an upperseat ring for a tire rim forming a part of the upper part of the pressand an annular surface on the inner cylinder, the arrangement being suchthat in the closed position of the press the upper seat ring is incontact with the annular surface on the inner cylinder.

3. A tire-vulcanizing press as claimed in claim 1, including a centraland downwardly extending rod having the locking device for cooperationwith the lower part of the press.

4. A tire-vulcanizing press as claimed in claim 3, in which the lockingdevice is a clamping sleeve which can be opened and clamped by means ofa clamping screw accessible from the outside of the press.

5. A tire-vulcanizing press as claimed in claim 3, including acompression coil spring providing the resilient means and having itslower end bearing against the lower part of the press and its upper endbearing against a shoulder on the rod.

1. A tire-vulcanizing press for vulcanizing preformed tire carcasses,including an upper part and a lower part, a mould having an upper halfon the upper part of the press and a lower half on the lower part of thepress, and an assembly on the lower part of the press having an outercylinder, a seat ring for a tire rim on the outer cylinder, a drivingsystem for the outer cylinder, the outer cylinder being movable axiallyby the driving system to eject a tire from the lower half of the mould,an inner cylinder within the outer cylinder, a locking device forholding the inner cylinder at a predetermined level, a heating bag whichmay be arranged when folded double in the annular space between theinner and outer cylinders, clamping rings connected to the innercylinder between which the edges of the bag may be clamped, andresilient means for urging the inner cylinder towards and against a partconnected to the upper part of the press during the closing of thepress.
 2. A tire-vulcanizing press as claimed in claim 1, including anupper seat ring for a tire rim forming a part of the upper part of thepress and an annular surface on the inner cylinder, the arrangementbeing such that in the closed position of the press the upper seat ringis in contact with the annular surface on the inner cylinder.
 3. Atire-vulcanizing press as claimed in claim 1, including a central anddownwardly extending rod having the locking device for cooperation withthe lower part of the press.
 4. A tire-vulcanizing press as claimed inclaim 3, in which the locking device is a clamping sleeve which can beopened and clamped by means of a clamping screw accessible from theoutside of the press.
 5. A tire-vulcanizing press as claimed in claim 3,including a compression coil spring providing the resilient means andhaving its lower end bearing aGainst the lower part of the press and itsupper end bearing against a shoulder on the rod.